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CONTENTS
Pa*
JflBLE Q
p COnTEflTT
1.
Introduction
3
2.
Power
On Preparation
5
3. Video
Display
format
6
4. Keyboard and Cassette
7
5.
Program loading
g
6.
Program Saving
. . . . .
10
7. Second Cassette Recorder
..,,....,,.,,
11
8.
System
Reset
12
9.
Software
,
12
APPENDIX
A. Technical
specifications
B.
Memory map and I/O map
C. ASCI I table

The design philosophy
of the
System
80 Is like
that
of most other
general
purpose computer
systems,
and has
great
expansion capability. The main
unit
(EG3003/4)
contains
a Central
Processing
Unit,
I/O devices and
a
mass storage device.
These
are the
Z80
CPU,
a keyboard,
a video
interface
and a
resident
cassette recorder.
The EG
3003
has
resident
16
Kilobytes
of RAM
(Random Access Memory) for
user's program
storage,
while
the EG3004 has
only
4K. The
system has a video
interface
and an
RF
modulator
to
display
the information
on
a VDU or
a
TV,
inTRODUCTIOn
Fig,
1.1

Beside the hardware configuration described,
the
System 80 has
a powerful
resident EXTENDED
BASIC Interpreter
which is compatible with that
of
TRS-80
Level II
BASIC.
An
optional S-100 bus
expansion box
is
designed
to be
connected to
main unit. More peripherals
can then be
linked
to the
system by plugging their standard
interface cards into the
S-100 bus
mother-board.
S-100
bus
is now
a
standard in the micro
computer industry, especially
for
computers
using 8080 or Z-80 CPUs,
TV
OR VDU
TELEPHONE
MODEM
EXPANDER
/
r
.. ,/
LiUJj/
ADDITIONAL
RAM
RS-232-C
SERIAL
PORT
&>
^
This
is
my family
I
4

The
System
80
is ready
to operate
rrriedietely
after unpacking
from the
carton
box. However, the user
shouid
adhere
to the
following
procedures.
a
Ensure that the power switch
is
in
the 'off
position.
b
Check
whether
the
AC
voltage
labelled
on the power supply
unit
is
the same
as that
of
your
country.
C Connect
the
power
plug
to
a
power line
socket.
d Connect
a V oeo
Display
Unit
to
the
system. The Unit can either
be an
ordinary
TV
set
or
a
video
monitor.
e
E-nwe that the
'Video
Cut'
switch
at
the
back
panel
s at
the
out
position.
The
display format
wil
be 64
characters/line.
Turn on
the
power
of
the
display
unit *irst,
then the
System 80.
g
A
message
'READY?' will
be
displayed
on
the
top left corner
of
the
display.
h
I*
no '9E- ADY'
message
is displayed,
go
to step (a) and check again.
i
After
the
READY?'
message
appears, the
user should
hit the NEW LINE key, then
another 'READY'
message
should
appear on
tie
bottom left
corr-er of tne display
j
Now,
the
System
is
at the
Active
Command
level.
You
can
type in commands
to
get
the
computer
to work
for
you.
Please refer
to the
Programming
Manual
for all
the
Active
Commands
available.
k
If
you want to have another display
*ormat,
please
read the next
section.
NOTE:
If the power
switch
is
turned off
for
any
reason, the
user shouid wait
at
least 15
seconds
before
turning the power switch on again,
power
on
PREPARATIOD
OFF
~~^
TV
or
X
N4DISHTQPI
OfSJ
NEW
LINE
*«»—
*!
r
h
i
b

3.1
FORMAT SELECTION
The
System 80
allows two kinds
of display
formats,
that Is,
(1),
64
characters
per line;
(2)
32
characters
per line. The purpose
of
the latter is to permit an enlarged
and
clear
character
display
when
a
television
set is
used,
3.2
64 CHARACTERS/LINE FORMAT
The
64 characters
per line
format
is
selected
whenever the
computer is turned
on and
the
VIDEO
CUT button is off. The user
may select
32
characters per line
by pressing
the VIDEO CUT button,
3.3
32
CHARACTERS/LINE
FORMAT
a) Press the VIDEO
CUT
button on the back panel.
b) Press the PAGE
button
on the front panel
to read either
the left
half
or the right
half of
the text on
the display.
3.4
SPACE
INSERTION
A
space
can
be inserted automatically
between characters
by typing
in
PRINT CHR$(23)
This
mode will be reset
by
NEW
or CLS command.
VIDEO DI/PLflY
FORfTlfiT
64 characters
per fine
VIDEO CUT
32 characters
per
line
i
VIDEO
'That's better
!'
ON
r
PAGE
CUT
i)

The
keyboard
acts
as
a man-machine
interface, while
the
cassette is
used for
mass
storage of programs and data.
4.1
Special
Function
Keys
PAGE
-
select page for
display
(refer
to previous
section).
Fl
—
isolate the
cassette from
the
control of
the computer
during
winding
and
rewind-
ing and allow
manual
cassette
motor
control.
BREAK -
break a
running
program
and return to the
Active
Command
Level.
NEWLINE
-
enter
a line
of
command
or data into the
computer.
BACKSPACE
—
cancel the
character previously
typed.
ESC -
the display
echoes
a
f
sign
which is an
exponent
sign used
by the
System.
CTL
-
move the
cursor
to the
beginning of the
next line.
SH IFT/CTL/I
-
tab function;
move
the cursor
8
spaces
to
the right.
SHIFT/CTL/Y
-
same
as print
CHR${23). See
section
3.4
SHIFT/BACKSPACE
-
delete
line,
4.2 Cassette
Recorder
The
cassette
recorder
is a high fidelity
audio recorder.
It
has
six piano keys
and
a
3-digtt counter.
The
keys function
the
same as those of
a normal recorder.
The
user
should
take the advantage
of the counter
for fast
program
locating.
Program
loading and
saving will be
discussed
in detail in
next
section.
KEVBOflRD
6
CPJ/ETTE
PACE
Fl
CASSETTE
RECORDER
POWER
CONTROL
SHIFT
TAPE COUNTER
SPACEBAR
BREAK. BACKSPACE
NEWLINE SHIFT
RECORD
REWIND fF
PLAY STOP/EJECT PAUSE
COVER

5.3
Checking
a Program
a) Read the
CLOAD command
(section
1.5 m the BASIC
Manual.)
b) Rewind
the
cassette tape
to
the
starting point
of the program.
c) Press the PLAY
button on the cassette
drive,
d) Type m
the command
CLOAD? from the
keyboard.
e) Hit the
NEW
LINE key.
Once the
computer finds
the program,
two asterisks
will appear on the
top right corner
of the display,
the
one on the right
will be flashing
if
comparison is successful
A READY
message
will appear
if the
comparison has been completed.
Otherwise, the word
BAD will
be
displayed.
i
PLAY
cioao?
**
or
BAD
NEW
LINE
5.4 Listing and Executing
a
Program
a) Read
the
LIST and
RUN
commands
(sections
1.9 and
1.11 in
the BASIC
Manual).
b)
Type in
LIST and hit the NEW
LINE key
(The
entire program will
be
listed
on
the
display).
c)
Type
in
RUN
and
hit the NEW
LINE key (The computer starts
executing the
program).
[new
lineJ
NEW
LINE
WARNING : CASSETTE LOADING
Although the cassette interface circuit
can tolerate
wide range
of input
signal level,
sometimes,
loading
error
may
occur.
The reason is that
so
many software
houses produce
TRS-80 compatible tapes and their quality
may
differ
a lot The only solution
is to do a
backup
for yourself
and use
the
backup copy for future
loading.
The backup procedure should
be:
—
0)
Put the TRS-80 compatible
tape into
second
cassette.
(2)
Connect the second
cassette
to
the computer.
(3)
Use CLOAD #—2, 'f command to load the
program
into memory.
(4)
Try
to
adjust
the second cassette volume if loading fails,
(5)
If
the program
is
successfully loaded, save it
onto a
blank
tape
with
cassette
#
1
.

Two cassette
recorders
are required in some applications
such
as
payroll and
account-
ing. In these applications,
old data have
to be read into the
computer sequentially from one
file and
output to another file
after processing
or updating. The main
unit already
has the
interface
for one
more cassette recorder. Signal
input/output
is through the DIN jack at the
back panel,
A cassette recorder
cable is packed with the
System.
Active
Commands
and instructions are provided
to
handle
this extra cassette,
These
are ;
—
(i)
CLOAD
#
-2, "M"
-
load a program called M from cassette
*2'.
(ii) CSAVE
#-2,
"M"
-
save a program onto
cassette
'2'.
(iii)PRINT#-2,A,B,C$
-store the
variables A
r
B and character
string C$
onto cassette
'2\
(iv) INPUT#-2
r
A,B,C$
-
input the variables A. B and
character
string C$
from cassette
'2'.
For further
programming details, ptease refer to the BASIC Manual, The operating
procedure
of the
cassette
'2'
for playing (reading in data) or recording
(outputting data
onto
the
tape)
is
same as
that
described in 4.1
/econo
CflXTETTE
RECORDER
Note;
—
The
user may have to
adjust output volume of his
cassette untif no error
occurs
during
cassette
loading.
The
System 80
may
have to be
reset
if invalid
data
is read
and
causes a dead loop.
WHITE
TO MtC
BLUE TO REMOTE
BLACK TO EAR
mm
VOLUME ma*
That's
my
heart-beat!!
11

The system must, in
some
cases be
reset. When, for example,
the machine is running in
a
dead loop. The Reset
Switch
is
located
at
the right side
of the back panel. Pressing
the
reset
switch causes
the computer
to
return
to
the
'READY' mode without
changing
the
memory contents.
The
system
runs in a dead
loop
in
the following
cases;
(1)
loading a
program from the cassette which
contains an
invalid file,
or
when the
volume of the recorder is
poorly
adjusted,
(2)
executing
LPRINT or LLIST instructions without
hooking up
a printer to
the
system or
having not turned
on the printer.
(3)
executing an
inappropriate
POKE
instruction.
The
CPU is reset everytime when the
power
is on.
Turning the
system off and on
immediately
is not
a good
practice;
because it may
cause improper initialization of the CPU.
Therefore, the user
should wait for about 15 seconds
before turning on the system
again.
/V/TEm RE/ET
Help!
The System
80
operates on
a
high level
language called BASIC. The system's
Extended
BASIC is
compatible with that of TRS80 Level fl BASIC, Therefore, TRS-80's
tapes can be
loaded into the system and run. Further details of the BASIC
language
are
explained in the BASIC
Manual.
The System can also load binary tapes that
contain
Z80 machine codes. For
loading
such tapes, please
refer
to
the SYSTEM command discussed in the BASIC MANUAL.
/OFTWflRE
12

m
POWER
CONSUMPTION
CASSETTE INPUT LEVEL
COMPUTER
OUTPUT
RECORDING
LEVEL
1
9
REMOTE SWITCHING CAPACITY
VIDEO OUTPUT
C2J
CONNECTORS
PIN ASSIGNMENTS
RPPEflDIH
fl
25W
(MAX.J
TECHfllCflL
1
V peak
to peak
/PECIFICATIOflf
0,3 V
peaktopeak
0.5 A
max at 6 V DC
—
2V peak
to peak
(Negative sync pulse)
DIN
JACK
PIN CONNECTIONS
FOR
ADDITIONAL
CASSETTE
1
-
REMOTE
2
-SIGNAL
GROUND
3
-
REMOTE
4
-
INPUT
5
-
OUTPUT
DIN
JACK
PIN CONNECTIONS FOR VIDEO INTERFACE
1 ~+5V
4
-
VIDEO OUTPUT
5
-GROUND
DIN JACK
VIEWED
FROM
REAR
SIDE OF THE SYSTEM.
EXPANSION
PIN
EOGE
VIEWED FROM
REAR SIDE
50
=3
49
13